Alberta Cancer Foundation

Understanding The Early Warning Signs Of Skin Cancer

Dr. Thomas Salopek. Illustration by Charles Burke.


Skin cancer is the most common type of cancer worldwide, and more than 80,000 Canadians are diagnosed with it every year. Fortunately, with early detection, most skin cancers can be treated effectively, which is why it is so important to know what to look for. Dr. Thomas Salopek, a professor in the University of Alberta’s Division of Dermatology, describes some of the early warning signs of skin cancer.

Q: What are some of the typical symptoms of skin cancer?

Most skin cancers are devoid of symptoms. It is only when they become a non-healing sore that patients present to their doctors. To help the public recognize early skin cancer, we encourage patients to self-examine [or] SCAN their skin. This handy acronym stresses importance of self-examination of the skin with each letter highlighting a warning sign of skin cancer. “S” is for sore, which is a spot that is scaly, itchy, bleeding or tender, that does not heal. “C” is for changing. “A” is abnormal relative to the other spots/growths on your body and “N” is for new.

Q: Are there common skin abnormalities to look out for?

One of the most common things that people will present with is an age spot, which typically starts to develop in people around 40 years of age. But, if a spot or growth is abnormal looking to you, talk to your doctor, especially if it’s changing.

Q: Are there certain types of skin cancer that are more difficult to diagnose?

The nonmelanoma skin cancers are notoriously difficult to diagnose from a lay person’s point of view, which is why you should always see your doctor if you notice any changes. Nonmelanoma skin cancers make up the majority of diagnoses and are usually curable if caught early. The two classic nonmelanoma skin cancers are squamous cell carcinoma and basal cell carcinoma. The latter almost invariably presents as a non-healing sore, but it can also be pigmented or look like a mole. Whereas squamous cell carcinoma usually starts as a rough patch that becomes thicker. Unfortunately, melanoma at its earliest stage, when it’s potentially curable, may just look like a discoloured patch and could be easily overlooked. It is only over time that one sees the features suggestive [of] cancer: asymmetry, irregular borders, colour variation, diametre greater than six milimetres (roughly the size of a pencil eraser), and evolving — the ABCDEs of melanoma.

Q: Where does skin cancer tend to develop?

Melanomas can occur anywhere on the body, but are predominantly seen in sun-exposed areas. In contrast, nonmelanoma skin cancers, squamous cell carcinoma and basal cell carcinoma are rarely seen in non-sun exposed areas. They are predominantly seen on the head/neck area, scalp (in bald individuals), upper extremities extending from the back of the hands to where your short-sleeved shirt typically ends.

Q: Who is most at risk for skin cancer?

In general, fair-skinned people are most at risk for skin cancer; it is very rare in people of colour. People with lots of sun exposure who burn easily and tan poorly are at risk for skin cancer. To minimize your risk of sun damage and thereby skin cancer, we encourage people to be prudent about sun exposure. When possible, avoid peak hours of sun exposure, [wear] protective clothing and regularly apply sunscreens of SPF 30 or higher throughout the day.